The present disclosure relates to a signal processing apparatus and a signal processing method, and more particularly to a signal processing apparatus and a signal processing method that can reproduce audio data including a very high frequency more securely while suppressing reduction in audio quality.
In recent years, there has been a wide use of audio data including a very high frequency signal component which is a higher-frequency band (for example, 20 kHz or more) than a frequency band commonly called an audible band (so-called data of high-resolution) (hereinafter referred to as high-resolution data).
This very high frequency may include a large amount of noise components formed of, for example, a noise shaper. It is difficult for a user to hear such very high frequency noise, so that the user is likely to perform volume adjustment based on reproduction volume of the audible band. Accordingly, the reproduction volume of the very high frequency noise is excessively increased, which overloads a reproduction device such as an amplifier and a speaker and can lead to breakdowns and the like.
Then, it is conceivable to suppress signal amplification (gain) at the time of reproduction to perform reproduction more safely. For example, there has been proposed a method of determining whether an input signal is noise or audio data with use of an autocorrelation and decreasing a gain when it is determined as the noise (for example, see Japanese Patent Application Laid-open No. 2008-543194).